The present invention relates to a charger to charge batteries, and especially relates to a charger preventing the failure of the electronic parts inserted into the case, due to the electrolyte leak from the battery or to water infiltration from the outside.
The charger has an attachment section provided in the case to allow the easy setting in at a fixed position and the easy taking out of the batteries or of the charging devices of electric apparatuses or the like mounted with a battery. Electrode windows are provided at a position facing the electrodes of the battery, charging contact points are exposed in these electrode windows. The charging contact points are connected to the electrodes of the batteries and charge the batteries.
When charging the batteries inserted into the attachment section of the case, some electrolyte leaks from the battery. For example, it happens that the electrolyte leaks when the battery is over charged. The reason is that when the battery is over charged, the inner pressure of the battery gets extremely high opening the safety valve. The leaking electrolyte penetrates inside the charger case through the electrode windows. The electrolyte that has penetrated into the battery case does not only cause a leakage of electricity or the like, but also provokes short circuits in the electronic parts or the corrosion of the electrical parts leading to a failure. The electronic parts are in a state easily leading to short circuits because the electrolyte that has penetrated inside the case, is a particularly conductive fluid. This drawback can be reduced by narrowing the space between the electrode windows and the charging contact points. But because the charging contact points are elastically deformable and are pushed by the charging terminals of the batteries or the like to be set to the attachment section, it is necessary to leave a space between the contacts points and the electrode windows which allows an elastically sufficient movement of the charging contact points. If the contact of the charging contact points with the electrode windows is made by rubbing, a smooth movement is no more realized and is the cause of the misconnection between the charger terminals and the charging contact points. For this reason, it is necessary to avoid the contact of the contact point with the electrode window, to surely allow the flexible pressing in of the charging contact point by the charger terminals of the battery or the like. It is therefore not possible to reduce the size of the electrode windows to avoid the penetration of the electrolyte.
Furthermore, not only electrolyte penetrates into the charger, but also water or the like via the electrode windows. Like the electrolyte, because water is also conductive, it causes leakage of electricity, and also causes electronic short circuits, or the corrosion of the electrical parts leading to a failure.
The present invention has been developed to avoid the drawback of the penetration of water or electrolyte into the case. The important scope of the present invention is to provide a charger which efficiently prevents the drawback of the electrolyte penetration inside the case through the electrode windows, and also surely prevents the internal short circuits and the corrosion.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.